4.1 Read Array Command
Upon initial device power-up and after exit from
deep power-down mode, the device defaults to read
array mode. This operation is also initiated by
writing the Read Array command. The device
remains enabled for reads until another command
is written. Once the internal WSM has started block
erase, program, or lock-bit configuration, the device
will not recognize the Read Array command until
the WSM completes its operation—unless the WSM
is suspended via an Erase-Suspend or Program-
Suspend command. The Read Array command
functions independently of the VPP voltage.
4.2 Read Query Mode Command
This section defines the data structure or
“database” returned by the Common Flash Interface
(CFI) Query command. System software should
parse this structure to gain critical information such
as block size, density, x8/x16, and electrical
specifications. Once this information has been
obtained, the software will know which command
sets to use to enable flash writes, block erases, and
otherwise control the flash component. The Query
is part of an overall specification for multiple
command set and control interface descriptions
called Common Flash Interface, or CFI.
QUERY STRUCTURE OUTPUT
The Query “database” allows system software to
gain critical information for controlling the flash
component. This section describes the device’s
CFI-compliant interface that allows the host system
to access Query data.
Query data are always presented on the lowest-
order data outputs (DQ0-7) only. The numerical
offset value is the address relative to the maximum
bus width supported by the device. On this device,
the Query table device starting address is a 10h
word address, since the maximum bus width is x16.
For this word-wide (x16) device, the first two bytes
of the Query structure, “Q” and ”R” in ASCII, appear
on the low byte at word addresses 10h and 11h.
This CFI-compliant device outputs 00H data on
upper bytes. Thus, the device outputs ASCII “Q” in
the low byte (DQ0-7) and 00h in the high byte
Since the device is x8/x16 capable, the x8 data is
still presented in word-relative (16-bit) addresses.
However, the “fill data” (00h) is not the same as
driven by the upper bytes in the x16 mode. As in
x16 mode, the byte address (A0) is ignored for
Query output so that the “odd byte address” (A0
high) repeats the “even byte address” data (A0 low).
Therefore, in x8 mode using byte addressing, the
device will output the sequence “Q”, “Q”, “R”, “R”,
“Y”, “Y”, and so on, beginning at byte-relative
address 20h (which is equivalent to word offset 10h
in x16 mode).
At Query addresses containing two or more bytes
of information, the least significant data byte is
presented at the lower address, and the most
significant data byte is presented at the higher
16 ADVANCE INFORMATION